The instant invention relates to medical equipment, and more particularly to a gastroenteric feeding tube for the enteral feeding of a patient by tube.
The use of tubes for the enteral feeding of patients is widely accepted in medical practice. In most instances, enteral feeding is accomplished through the use of a gastroenteric feeding tube which is installed in a patient so that it extends through a nostril, through the esophagus, into the stomach and sometimes into the jejunum area of the intestines of the patient. Generally, it has been found that once a feeding tube has been installed in a patient in this manner, it can be maintained in the patient for up to a month or more and it can be utilized throughout this period for effecting nutritional feeding of the patient at regular intervals. In this regard, it has been found that generally enteric feeding can provide substantially more nutritional feeding of hospitalized patients than other artificial feeding methods, such as intravenous feeding. In fact, it has been found that gastroenteric feeding is generally preferable for both medical and nutritional reasons and that the malnutrition and weight loss effects which often occur when other types of artificial feeding methods are utilized for prolonged periods of time can often be avoided with gastroenteric feeding.
Generally, most of the heretofore available gastroenteric feeding tubes have comprised elongated tubular members having distal and proximal ends and having apertures therein adjacent the distal ends thereof, and weighted bolus portions which are secured on the distal ends of the tubular members thereof. Feeding tubes have generally been constructed of materials, such as silicone, having flexibilities which are sufficient to enable them to be passed through the nostrils of patients and obviously both the bolus and tubular portions of the heretofore available gastroenteric feeding tubes have been dimensioned to be received through the nostrils of patients without causing significant trauma. Further, many of the heretofore available feeding tubes have been formed with longitudinally extending X-ray opaque stripes thereon so that it can be easily determined whether or not they are properly installed in patients. The weighted bolus sections of tubes of this general type have been provided in order to prevent the distal ends of the tubes from being either partially or completely expelled from the stomachs of patients as a result of regurgitation. It has been found that this feature is particularly important since it is possible for the distal end of a feeding tube to be passed into a lung of a patient if it is expelled from the patient's stomach by regurgitation and this can cause feeding formula to be introduced into the patient's lung. Obviously therefore, it is extremely important that a feeding tube include a bolus section which has sufficient weight to maintain the tube in properly installed relation in a patient. Generally, it has been found that it is preferable for a feeding tube of this type to be installed in a patient so that the distal end of the tube is disposed in the jejunum area of the patient's intestines which is located just past the patient's pyloric valve. In this regard, generally it has been found that when a feeding tube is installed in a patient in this manner, highly effective and nutritional feeding of the patient can be accomplished, and it has also been found that the risk that the tube will be partially or completely expelled by regurgitation is substantially reduced.
Most of the heretofore available feeding tubes have generally been too flexible to permit their installation in patients without the use of some means for increasing their rigidity. This is because the tubular members of most feeding tubes have generally been constructed of highly flexible materials, such as silicone rubber, in order to minimize patient discomfort and also because the tubular members of most feeding tubes have had apertures therein adjacent the distal ends thereof which have made them extremely succeptible to collapsing and kinking. For these reasons, heretofore it has generally been the practice to intubate feeding tubes in patients using temporary wire or nylon stylets in the tubular members thereof to provide increased rigidity therein. While the use of stylets has proven to be an effective method of installing feeding tubes in patients, it has been found to have some very serious disadvantages. Specifically, because feeding tubes necessarily have apertures therein adjacent the distal ends thereof for passing feeding formula to patients, when a stylet is used to install a feeding tube in a patient, it is possible for the distal end of the stylet to inadvertently pass through one of the apertures in the tube and cause substantial damage to or even puncture a wall of the patient's esophagus, stomach or intestines. This can result in extremely serious injury to the patient and sometimes can even result in death. Hence, the installations of feeding tubes in patients have often involved substantial risks to the patients, and it has generally not been the practice for a nurse or technician to be permitted to install a feeding tube in a patient without the supervision of a doctor.
The instant invention provides an enteric feeding tube which can be effectively installed in a patient without the use of a stylet so that the risks associated with the installation of the tube are substantially reduced. The feeding tube of the instant invention comprises an elongated tubular member or shaft having distal and proximal ends, an enlarged intermediate portion which extends from the distal end of the shaft and an enlarged weighted bolus which extends from the intermediate portion. In contrast to most of the heretofore known feeding tubes, the tubular shaft of the feeding tube of the instant invention has an imperforate side wall. A lumen extends longitudinally through the tubular shaft, and instead of communicating with the exterior of the tube through side apertures in the shaft, it extends to the intermediate portion and communicates with a side aperture in the intermediate portion for passing feeding formula to a patient. Hence, the distal end of the tubular shaft is not prone to kinking or collapsing, and since the intermediate portion is formed with an enlarged sectional dimension, it is inherently more rigid than the shaft and it also is not prone to collapsing or kinking, even though it has a side aperture therein. The weighted bolus of the feeding tube is formed with a weight therein which is sufficient to maintain the bolus, the intermediate portion and the distal end of the shaft in the stomach or jejunum area of a patient, and the bolus is formed so that it has sufficient flexibility to permit the passage thereof through a nostril of a patient during the installation of the tube in the patient. The shaft and the intermediate portion are formed so that they have sufficient flexibility to permit their passage through a nostril of a patient during the installation of the tube in the patient, but so that they nevertheless have sufficient rigidity to permit the installation of the tube in the patient without the use of a stylet in the shaft. The intermediate portion of the tube is preferably formed with an open interior passage which extends from the lumen of the shaft to the side aperture in the intermediate portion and the passage and the side aperture preferably each have cross-sectional areas which are at least as great as the cross-sectional area of the lumen in the tubular shaft to permit the side aperture in the intermediate portion to be effectively utilized for dispensing a feeding formula into the stomach or intestines of a patient. The passage in the intermediate portion preferably terminates adjacent the portion of the side aperture therein which is closest to the bolus so that it does not leave a "dead space" in the distal end of the passage in the intermediate portion which would tend to collect feeding formula and become clogged. The intermediate portion is formed with a greater sectional dimension than the tubular shaft of the feeding tube so that it is resistant to kinking or collapsing, despite the fact that the intermediate portion has at least one side aperture therein, and the bolus preferably has substantially the same cross-sectional dimension as the intermediate portion. The shaft of the feeding tube preferably has a sectional dimension of between 0.08 and 0.16 inches, a wall thickness of between 0.015 and 0.035 inches, and the lumen in the tubular shaft preferably has a sectional dimension of at least 0.05 inches. The shaft is preferably made of a material having an A Durometer Scale hardness of between 60 and 100. The intermediate portion which extends from the tubular shaft is preferably formed so that it is at least as rigid as the shaft, and the intermediate portion is preferably made of a material having an A Durometer Scale hardness of between 50 and 100. The bolus preferably comprises a casing portion and weight means in the casing portion, and the casing portion is preferably made of a material having an A Durometer Scale hardness of between 45 and 90. Preferably, the shaft, the intermediate portion, and the casing portion of the bolus are made of a polyether based polyurethane, since it has been found that the components of the feeding tube can easily be made so that they have the desired degrees of stiffness from a compound of this type, and it has also been found that a polyether based polyurethane generally maintains its flexibility, even after prolonged exposure to gastric mucosa.
Accordingly, it is seen that the feeding tube of the instant invention has substantial advantages over the heretofore available feeding tubes. Specifically, because the feeding tube is constructed so that the side apertures therein, which are provided for passing a feeding formula into the stomach or intestines of a patient extend, through the enlarged intermediate portion rather than through the wall of the distal end portion of the tubular shaft, the distal end portion of the shaft is substantially less prone to collapsing and kinking during the installation of the tube in a patient. Further, because the intermediate portion is constructed in an enlarged dimension, kinking of the intermediate portion is not normally a problem during the installation of the tube in a patient, despite the fact that the intermediate portion has at least one side aperture therethrough. Because of these features and because of the stiffnesses of the components of the tube as hereinabove specified, the feeding tube can be installed in a patient without the use of a stylet. Further, because of the stiffnesses of the components of the tube, the feeding tube can be installed in a patient without causing a significant degree of trauma to the patient, and because the feeding tube is constructed of a polyether based polyurethane, it can be left in a patient for a prolonged period of time without causing irritation to the patient.
Feeding tubes representing the closest prior art to the instant invention of which the applicant is aware are disclosed in the U.S. Pat. Nos. to Wilkins, No. 1,736,182, Dykstra et al, No. 4,410,320, and Harrison et al, No. 4,390,017, and in the copending U.S. application to Brodsky, Ser. No. 484,413. However, since none of the devices disclosed in these references embody the novel features of the feeding tube of the instant invention which enable it to be intubated in a patient without the use of a stylet, they are believed to be of only general interest.
Accordingly, it is a primary object of the instant invention to provide a gastroenteric feeding tube which can be installed in a patient without the use of a stylet.
Another object of the instant invention is to provide a feeding tube which can be installed in a patient with a minimum of risk to the patient.
As even further object of the instant invention is to provide an effective gastroenteric feeding tube which can be installed in a patient by a nurse or a technician without the supervision of a physician.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.